Air conditioner for heating,cooling,and pressurizing vehicle cabs



United States Patent S T N w A .IP "in a T A e T 8 D E W N U N U .m s n0 c k W n mm e w.m m a W WM DP w 0 t n e v n I 2 H.

XXXXXXX 9392249 BQHSQISQM 2 26 2 6 61 6 m. Tn a WM ML mu L t .t l o n el en.l W m H mm m flv mo awa FALRSGSC 47906 66666666 99999999 mmmmmwmu40867965 700070371 193700 71112 6 2 2 3332333 r ,J u" .m a S WS n e m wmem mnm .mW e o w s bm el ry-I. l 88W 8 WM HR a 0m a L.m m J9 n n SS01.10 k 8 m roe h4e a D. o 1 m 0 m W. 1 S 7MASM 0 N n .w e m m e .w :m md P ei pmmfi AFPA a C IP- Of Wisconsin Primary Examiner Robert A. OLearyAssistant Examiner- Theophil W. Streule All0rneyWheeler, Wheeler, Houseand Clemency ABSTRACT: Heating and cooling units assembled in a housingpreferably extending across a vehicle cab above the windshield can beoperated selectively to heat or cool air admitted either byrecirculation from the cab or from out of doors and optionallypressurized by a fan after traversing a 4 G M m "M ou 1 O C A m m m m w0V.w m G m R E .m m NEW O m Um me N 0 m h .l u

mNC S AAS U m n filter. The filter and out-of-door air inlet arepreferably mounted externally of the cab but directly communicating [Sl]Bh 3/00 with the housing of the interior, air circulation being con-[50] Field ofSearch...............i........................ /4244;trolled manually by means of dampers. The filter is externally 98/2-4,l4: 62/259RC; 62/259; 165/23; 98/25 accessible for cleaning.

Patented Aug. 4, 1970 Sheet diaries US. PATENT 3,522,839 AIR CONDITIONERFOR HEATING, COOLING, AND PRESSURIZING VEHICLE CABS BACKGROUND OFINVENTION There is a long-standing need for a complete air conditionerparticularly designed to render more comfortable the cabs of tractors,agricultural implements, and military vehicles where extreme conditionsof heat and cold and dirt are encountered.

SUMMARY OF THE INVENTION There are great advantages in having the freshair inlet housing and filter disposed externally in whatever positionwill supply the cleanest air, the external housing for the filter havingon the outside of the cab a removable cap to facilitate filterreplacement.

In the disclosed organization, any desired proportions of external andinternal air may be passed through the filter to a blower fan which, forcompactness, may have its motor inside ofthe annular filter. Inpreferred embodiments, this places the motor largely externally withregard to the cab. Air from the outside and recirculated air from thecab can be apportioned as desired. The shutters or valves forcontrolling recirculating air and admission of external air areindividually controllable manually, as is the motor of the blower, thelatter having a 3-position switch for giving fast and slow motor speedsin addition to stop.

The air discharged through the cooling radiator is directed back acrossthe front seat of the cab whereas the discharge from the heatingradiator is directed downwardly across the windshield for defrostingpurposes as well as for heating the cab.

At least the cooler is desirably controlled by a thermostat. This can beset for any desired temperature and controls the clutch oftherefrigeration compressor to interrupt the drive to the compressorwhenever the desired temperature is reached.

The damper valve which determines in what relative proportion thefan-propelled air will pass through the cooler radiator or the heaterradiator is desirably also connected to control a valve in the supply ofengine-heated water admitted to the heater radiator, the arrangementbeing such that the greater the amount of air traversing the radiator,the greater will be the opening of the valve which controls hot watercirculation.

Another desirable arrangement is that which permits the operator notonly to choose the valve setting which will determine how much air isderived from out of doors and how much is recirculated from the cab, butalso to determine what proportion of the air propelled by the blower isdischarged through the heater and how much through the cooler. Althoughthe thermostat controls only the cooler, the combination of thermostatcontrol and control of the direction of air delivery enables theoperator to maintain substantially constant temperature under allconditions.

Pressurizationof air admitted from out of doors maintains the entirecabcontinuously at somewhat superatmospheric pressure of filtered air, thustending to exclude dust.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary view inperspective looking toward the apparatus from the rear of a cab in whichit is mounted, portions ofthe cab roof being broken away.

FIG. 2 is a view in rear elevation (as viewed in the direction of cabadvance) showing one complete embodiment of the invention.

FIG. 3 is a view taken in section on the line 3--3 of FIG. 2.

FIG. 4 is a view taken in section on the line 4--4 ofFIG. 2.

FIG. 5 is a view taken in section on the line 5--5 ofFllG. 2.

FIG. 6 is a view taken in section on the line 6--6 ofFIG. 3.

DETAILED DESCRIPTION An air conditioner housing Ill) is preferablymounted at the top front of a vehicle cab I2 immediately beneath the cabtop I4 and adjacent its windshield 16. It is broadly immaterial whatkind of a vehicle supports the cab. As already indicated, it mayfrequently comprise a truck, a tractor, an agricultural implement, or amilitary vehicle. It may be assumed that the prime mover of the vehicleis an internal combustion engine, the coolant of which can be used inthe heating radiator of the air conditioning unit. For the coolingradiator, a conventional heat-absorbing condensing radiator willordinarily be used in a refrigeration system (not shown) comprising amotor-driven compressor and heat-rejecting radiator.

As best shown in FIG. 3, the housing 10 contains a heating radiator 18near its front or windshield side, and an evaporator or other coolingradiator 20 at its rear (toward the drivers seat). A pipe 22 derivingcoolant from the engine (not shown) leads to the radiator 18 and a pipe24 leads back to the cooling radiator (not shown) or to the engine. Thecirculatory system includes a flow-controlling valve 26 operable ashereinafter explained. Beneath the heating radiator 18 and immediatelyabove the windshield 16 is a foraminous bottom wall 28 provided withopenings 30 for directing the hot air downwardly across the windshield16 after it has traversed the cab heating radiator 18.

The rear wall 32 is preferably obliquely inclined as shown in FIGS. 4and 5. Where it extends in front of the cooling radiator 20, it isprovided with a number of adjustable baffles 34 for controlling thedirection of delivery of air which has traversed the cooling radiator20.

The air to be passed over the respective radiators is derived incontrollable proportions from two sources and pressurized by a fan rotor36 driven by motor 38. Such of the air as comes from the exterior of thecab passes through a foraminous screen or plate 40 which is located inexternal housing 42 on the roof 14 of the cab. It is desired toemphasize the fact that this external housing need not be in theposition illustrated. As shown, the screen 40 is at the rear. It isplaced wherever dust and dirt are at a minimum whether this involvesdirecting it rearwardly or forwardly or laterally. It need not even beon the forward lefthand side of the cab roof as shown, although this isits preferred location because it can then be directly above the housingI0 in which the various radiators and controls are disposed.

In any event, the air admitted through the screen 40 in the externalhousing 42 is required to pass through a filter 44 for which the housing42 has a removable cover at 46 to enable the filter readily to bereplaced outside the cab. The filter is surrounded by a plenum chamber48 so that all sides of the cylindrical filter are exposed to receiveoutside air. It is convenient to locate inside the filter the motor 38which drives the blower fan 36. Thereby the motor is cooled by incomingair. The motor extends downwardly through registering openings 51 in theexterior housing 53 in the cab top and 55 in the conditioner housing andinto another plenum chamber at 52 to which the air is admitted from theinterior of the filter and from which the air finds access to theinterior of the blower 36.

If the air is being recirculated from the interior of the cab, it doesnot have to traverse the filter 44, since it is presumably alreadydust-free. Instead, after it passes through the grill 54 and, subject tothe control of plate valve 56, it is admitted through valve-controlledport 57 directly to the plenum 52 and thence through ported partition 57to the blower 36. In

' the position of the plate valve shown in FIG. 5, no air is being Theair delivered from the blower 36 passes through a I volute fan casing 62and emerges either to the heater or cooler, or is divided therebetween,according to the position of the valve plate 64. In the full lineposition in which the valve 64 is illustrated in FIG. 3, all air isbeing deflected through the cooler to emerge in the cab through thevarious openings-34, which are directed toward the seat. In the dottedline position of plate 64 as shown in FIG. 3, all air would be deflectedthrough the heating radiator 18 to emerge through openings 30 forpassage downwardly over the windshield for defrosting purposes,.beingthen used for the heating of the cab.

The blower motor 38 is controlled by a 3-position switch 68 which is onthe inclined rear panel 32 of housing 10. Immediately above the switchthere is a thermostat 70 which can be set for any desired cabtemperature and which, when it responds, disengages the clutch whichdrives the compressor of the air conditioner, thereby arresting thesupply of coolant to the cooling radiator 20. This direct control ispreferred to a possible substitute system in which coolant chilled in anevaporator elsewhere is passed, like the heating fluid, through pipesleading to the radiator 20, the control being, in such a case, like thecontrol afforded by valve 26 or by starting and stopping the pump whichcirculates the coolant through the radiator.

As stated, the air used for conditioning the cab can be derived indesired proportions either from the outside or by recirculation from thecab and it may be passed in desired proportions either through theheating radiator or the cooling radiator. In both cases theapportionment is presumably effected by hinge valve plates in the mannernow to be described.

There are two levers 72 and 74 pivoted for movement through slots in theinclined rear panel 32. The lever 72 determines relative i'low from thesources of air. It is'connected by a Bowden wire or a similar control at76 to the valve plate 56 shown in FIG. 5. The lever 74 controls therelative disposition of the air. This lever'is connected by a Bowdenwire or like control 78 to the crank 80 of hot water valve 26. The link82 connects the valve with an arm 84 on the hingedly swingable plate 64which determines what part of the air pressurized by fan 36 will passthrough the cooling radiator 20 and what part will traverse the heatingradiator 18 as shown in FIG. 3. Normally (but not necessarily) thedamper plate 64 will be in one extreme position or the other.Appropriate partition means 60 provides the ports controlled by thevalve or damper plates or vanes 56and 64. Y

The manner in which the valve 56 is operated is illustrated in FIGS. 4and 5. The lever 72 has a fulcrum at 86 and is pivotally connected at 88to the reciprocable wire 90 which operates in the Bowden wire sheath 76.Where the wire 90 emerges from the sheath, it is connected at 94 to thevalve plate 56 in a position close to the fulcrum 96 on which such plateis pivoted.

The manner in which the valve 64 is operated is shown in FIGS. 3 and 6.Here the Bowden wire 78 leads to the crank 80 of the valve 26 in pipe22, motion being thence communicated through the link 82 to the arm 84on the hinged valve 64.-

We claim: 7

l. A vehicle cab air conditioner comprising a housing having anadmission inlet from the cab for recirculation, and having an externalair admission inlet, and having a hot air outlet, and a cold air outlet,means defining a fan chamber, an air propelling fan in said chamber, afirst partition means and damper for selectively admitting air fromrespective inlets to said fan chamber, a second partition means anddamper for defining separate passages leading from the fan chamber tothe respective outlets, heating and cooling radiators in the passages inthe path of fan-propelled air directed to the hot air outlet and thecold air outlet respectively.

2. A vehicle cab air conditioner according to Claim 1 in furthercombination with a cab having a top and a windshield, the said housingbeing mounted near the top and the windshield, the top having an openingand having a secondary housing above the opening and communicatingthrough the opening with the first-mentioned housing, the external airinlet being provided through the secondary housing and said openmg. A

3. A vehicle cab air conditioner according to Claim 2 in which saidsecondary housing is provided with an air filter for air en route tosaid fan, said secondary housing being provided with a removable closurethrough which said filter is accessible for change, said filter beingannular in form and said fan having a motor extending upwardly throughthe opening in said first-mentioned housing into the second-mentionedhousing and within the annular filter.

4. The combination with a vehicle cab having a top pro.- vided with anaperture, of a first housing disposed within the cab and extendingacross the aperture, a second housing on top of the cab top and having ascreened air inlet externally of the cab and an opening communicatingthrough the cab top aperture with the first-mentioned housing, a filterin the second housing interposed between the external air inlet of thesecond housing and the opening which communicates with the firsthousing, the second housing having an access door giving communicationwith said filter externally of the cab, the first-mentioned housinghaving a separate inlet within the cab for the admission of cab air, afan mounted within the firstmentioned housing and having an inletcommunicating with said cab air inlet, a damper valve for controllingrelative flow of air from the respective inlets through the filter tothe fan, said first housing having separate heating and cooling airoutlets and means for guiding air from the fan to the respectiveoutlets, damper valve means for controlling relative flow through saidlast-mentioned respective air guiding means, and heating and coolingradiators respectively disposed in the first housing in the path of airguided to the respective outlets.

S. The combination set forth in Claim 4 in which said fan has a motorprojecting through the cab top aperture and partially disposed withinsaid filter.

